Circulating fibronectin affects bone matrix, whereas osteoblast fibronectin modulates osteoblast function

• Verfasst von: Bentmann, Anke [VerfasserIn]
• Verfasst von: Kawelke, Nina [VerfasserIn]
• Verfasst von: Moss, David [VerfasserIn]
• Verfasst von: Zentgraf, Hanswalter [VerfasserIn]
• Verfasst von: Bala, Yohann [VerfasserIn]
• Verfasst von: Berger, Irina [VerfasserIn]
• Verfasst von: Gasser, Juerg A [VerfasserIn]
• Verfasst von: Nakchbandi, Inaam [VerfasserIn]
• Titel: Circulating fibronectin affects bone matrix, whereas osteoblast fibronectin modulates osteoblast function
• Verf.angabe: Anke Bentmann, Nina Kawelke, David Moss, Hanswalter Zentgraf, Yohann Bala, Irina Berger, Juerg A Gasser, and Inaam A Nakchbandi
• E-Jahr: 2010
• Jahr: 2010 Apr
• Umfang: 10 S.
• Fussnoten: Gesehen am 17.01.2023
• Titel Quelle: Enthalten in: Journal of bone and mineral research
• Ort Quelle: [Oxford] : Oxford University Press, 1986
• Jahr Quelle: 2010
• Band/Heft Quelle: 25(2010), 4, Seite 706-715
• ISSN Quelle: 1523-4681
• DOI: doi:10.1359/jbmr.091011
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: bone formation
• Sach-SW: bone matrix
• Sach-SW: fibronectin
• Sach-SW: liver
• Sach-SW: osteoblast
• K10plus-PPN: 1831282259

Abstract

The bone matrix is composed mostly of collagen, but the initial and continuous presence of fibronectin was found to be crucial for collagen matrix integrity in vitro. It has been assumed that osteoblasts produce the fibronectin required for bone matrix formation. Using transgenic mice, we conditionally deleted fibronectin in the osteoblasts and in the liver using the cre-loxP system. We also used mice with mutated fibronectin and conditionally deleted β1-integrin in osteoblasts to identify the receptor involved in fibronectin effects on osteoblasts. Conditional deletion of fibronectin in the differentiating osteoblasts [using the 2.3 kb collagen-α1(I) promoter] failed to show a decrease in fibronectin amount in the bone matrix despite evidence of successful deletion. Using these mice we established that osteoblast-derived fibronectin solely affects osteoblast function. This effect was not mediated by integrins that bind to the RGD motif. Conditional deletion of fibronectin in the liver showed a marked decrease in fibronectin content in the matrix associated with decreased mineral-to-matrix ratio and changed biomechanical properties but had no effect on osteoblasts or osteoclasts. In conclusion, osteoblast fibronectin affects osteoblasts function. This does not seem to be mediated by the RGD motif on fibronectin. In contrast, liver-derived fibronectin affects bone matrix properties without affecting osteoblast or osteoclast function. A novel role for liver-derived circulating fibronectin thus was defined and delineated from that of locally produced fibronectin. © 2010 American Society for Bone and Mineral Research